Flight Dynamics Model

A Flight Dynamics Model (FDM) is a set of math equations used to calculate the physical forces acting on a simulated aircraft, such as thrust, lift, and drag. FlightGear supports several different types of flight dynamics models. Every aircraft simulated by FlightGear must use one of these models.

LaRCsim was originally developed by NASA, and was the first FlightGear FDM, now replaced by JSBSim and YASim.

JSBSim was originally developed specifically for FlightGear, and has been the default FlightGear flight dynamics model since 2000. In addition to airplanes JSBSim also supports rockets, helicopters and lighter than air aircraft.

UIUC was developed by the UIUC Applied Aerodynamics Group at University of Illinois, based on LaRCsim, and includes additional features, such as the ability to simulate aircraft icing. UIUC lacks ground interaction.

YASim is yet another FDM using different calculation methods. YASim supports airplanes and helicopters. It was introduced in FlightGear version 0.7.9 in 2002.

FlightGear can also be set up to render using inputs from an external FDM source, such as from MATLAB.

Other custom FDM have been written for specific aircraft types, such as for hot air balloons.

Currently, FlightGear is the only graphical flight simulator to support all of these flight dynamics models.